Access to the Internet has experienced widespread growth. Owing to the growth in access has been the decreased cost of the software and hardware necessary for gaining access. However, notwithstanding the decreased cost of the hardware necessary for accessing the Internet, a significant segment of the population still cannot afford the costs associated with the traditional hardware necessary to access the Internet. Thus, while the Internet has the potential to positively impact people's lives, economic barriers remain a substantial impediment to many. It follows that a need exists for a less expensive Internet access means to reach that segment of the population that cannot ordinarily afford an Internet access system.
Ordinarily, one must sacrifice performance to provide a more affordable Internet access system. Thus, Internet access system designers have sacrificed performance as they looked for ways to save costs. At least one prior Internet access system takes advantage of the circumstance that a great number of homes already have televisions and use the television CRT and sound system through which the output of a Internet application session is conveyed to the user. This prior art solution however features complex customer electronics that rival the cost and complexity of most desktop Internet access systems. Moreover, this prior art solution further requires a separate physical transport channel for the bi-directional communications between each STB 500 and the Internet Service Provider (ISP).
Most homes are also connectable to a Residential Broadband (RBB) Access Network. A generic cable-television (CATV) Hybrid Fiber Coaxial (HFC) network is an example of such an RBB network. Referring to FIG. 1, a generic HFC network is characteristically hierarchical and comprises a Metropolitan Headend 92 coupled to a plurality of local Headends 94, each local Headend 94 being further coupled to a plurality of Nodes 96. In a point-to-multipoint (PTMP) Access Network, each Node 96 is further coupled to a plurality of Set-Top-Boxes (“STB”) 500 via a shared coaxial line—typically through a local interface 98 that provides bi-directional amplification of the HFC network communications.
The HFC network is currently used as a transport layer to deliver digitally compressed CATV programming to homes. Particularly, current digital CATV systems use MPEG2 transport streams (TS) and require that the home display device include a MPEG2 decoder. MPEG2 TS comprise audio, video, text or data streams that further include (PIDs), Program Identifiers. A PID identifies the desired TS for the MPEG2 decoder and is mapped to a particular program in a Program Map Table (PMT). Thus, a PID table and PMT within the decoder define the possible program choices for a digital CATV decoder and tuning a program for a digital CATV STB 500 comprises joining a TS of MPEG2 encoded frames. The PID table and PMT are remotely updated by the CATV service provider when the viewers choices for programming change.
MPEG2 compression is well known in the art. MPEG2 compression features both spatial and temporal compression. MPEG2 spatial compression comprises an application of the Discrete Cosine Transform (DCT) on groups of bits (e.g. 8×8 pixel blocks) that comprise a complete and single frame of visual content to distill an array of DCT coefficients that is representative of the frame of visual content. The resulting array of DCT coefficients are subsequently submitted to Huffman run-length compression. The array of compressed DCT coefficients represents one frame of displayable video and is referred to as an MPEG2 Intra frame (I-frame) when combined with a PID identifiable by a STB 500.
Temporal compression in MPEG2 comprises using knowledge of the contents of the prior video frame image and applying motion prediction to further bit reduction. MPEG2 temporal compression uses Predicted frames (P-frames) which are predicted from I-frames or other P-frames, and Bi-directional frames (B-frames) that are interpolated between I-frames and P-frames (For a discussion of MPEG-2, see B. Haskell, A. Puri, A. Netravali, Digital Video: An Instruction to MPEG-2, Kluwer Academic Publishers (1997)). An increased use of B-frames and P-frames account for the greatest bit reduction in MPEG2 TS and can provide acceptable picture quality so long as there is not much motion in the video or no substantial change in the overall video image from frame to frame. The occurrence of a substantial change in the video display requires calculation and transmittal of a new I-frame. An MPEG2 Group of Pictures (GoP) refers to the set of frames between subsequent I-frames.
The HFC network may also support upstream data communication from each STB 500 in the 5-40 MHz frequencies. If so, upstream data communication is typically supported between each STB 500 and upstream communications receiving equipment 97 (hereinafter “RCVR 97”) situated either at the Node 96 or the Headend 94. Upstream communication from each STB 500 enables requests for special programming to be communicated to the cable television service provider (e.g. request a PID associated with a particular pay per view program). Upstream data communication also conveniently permits collective management of the plurality of STBs 500 by an administrative function that is conveniently located elsewhere on the HFC.
Thus, one potential means of providing Internet access uses the RBB network such as the CATV HFC network as the transport layer through which bi-directional data communications are conveyed to and from an ISP. However, the upstream bandwidth on the HFC network is limited, and will without doubt come under increased demands as this prior art solution and other applications seek to take advantage of this HFC network capability. Therefore, the efficient use of this limited upstream bandwidth presents a hurdle to creators of bi-directional communication based applications implemented on the HFC network.
One potential approach that accommodates the limited upstream bandwidth uses the home television as a display device, and a STB 500 incorporating the functions of a “thin” remote client. The remote client may be incorporated into the STB 500 for convenience or into the display device. See FIGS. 2a and 2b. The remote client requires only that amount of hardware and software necessary to send Internet application commands and a unique STB 500 identifier upstream to the RCVR 97. At the Headend 94 or Node 96, application commands and STB 500 identifiers are conveyed from the RCVR 97 to an Ethernet Switch that is further coupled to a plurality of distinct AV content processing boards.
FIG. 3 depicts a representative diagram of this prior-art solution that can accommodate delivering MPEG video content to multiple remote clients via the HFC network. In this solution, each AV content processing board establishes an Internet application session for each remote client that requests Internet AV content. The Internet AV content processing board recovers the requested Internet content and outputs the AV content to the STB 500 in a MPEG transport stream appended to a PID expected by the STB 500.
This solution presents a more affordable system for the end consumer as it shifts a substantial portion of the hardware and software costs that would typically impact the home up the RBB network to the CATV services provider, where the cost can be amortized over many users. This approach also is permits the implementation of a relatively high performance Internet AV content delivery system. In contrast, the prior art solution suffers substantial cost and complexity for the RBB administrator and would likely therefore deter a RBB administrator from implementing the system depicted in FIG. 3. It follows that reducing costs for the RBB administrator has the potential to increase industry acceptance of Internet AV content delivery over the HFC network. Accordingly, there is a need for less expensive system design that is capable of processing and retrieving the Internet content requested by remote clients, and delivering that Internet content in a format recognizable by remote clients.